Shortly after starting Boston Beer, Koch realized that in order to get his beer, Samuel Adams, to market, he first needed to learn how to sell it — and that's something the Harvard Business School alum said the Ivy never taught him.

While the university has "dozens of courses on marketing," he explained, it had none on selling, so Koch headed to the HBS bookstore and bought the one relevant book he could find: "How to Master the Art of Selling" by Tom Hopkins.

"It had this cheesy guy in a polyester suit, grinning, on the cover," he recalled. "There were some sleazy parts, but the gist of it was quite good. He actually went on to write 'Selling for Dummies.' It was very worthwhile."

The self-taught salesman realized that selling isn't the "ignoble activity" we've been culturally trained to think of it as. "I learned, against all my expectations, that done right, it is very noble," he said. "You are helping the customer achieve their objectives, so you have to learn to listen and empathize."

"You've got 30 seconds when you walk into the bar — and you have to figure out who their customers are, what their economics look like, how they make money, who's the decision maker, what's their thought process, what's their communication style … so you are intellectually challenged at a very high level."